The West African regional grouping, Ecowas, has dismissed as a negotiating tactic the announcement by Niger’s coup leader that civilian rule cannot be restored for three years.
The organisation’s political commissioner, Abdel-Fatau Musa, said the timetable was unacceptable.
On Saturday, Gen Abdourahamane Tchiani said a national dialogue was needed to lay the foundations for a new political order in Niger.
Ecowas has threatened military action to restore the ousted president.
Crowds have again rallied in the capital, Niamey, in support of the coup.
But correspondents say others opposed to the military takeover are afraid to public express their views.